High volume, low back-pressure gas scrubber

ABSTRACT

In one aspect of the invention there is provided a gas scrubbing system for removing contaminants from a flow of fluid, comprising a container having an interior volume, an inlet for receiving the flow of fluid and an outlet for dispensing the stream of fluid, a treatment liquid, a porous medium positioned in the interior volume, between the inlet and outlet, said porous medium providing a high surface area to facilitate chemical interactions between the fluid flow and the treatment liquid and means to apply the treatment liquid onto the porous medium. A contact cell aspect of the porous medium and a method aspect are also provided.

CROSS REFERENCE TO RELATED APPLICATION

This application is a regular application of U.S. Provisional PatentApplication Ser. No. 60/893,881 filed Mar. 8, 2007 and entitled “HIGHVOLUME, LOW BACK-PRESSURE GAS SCRUBBER”, the entirety of which isincorporated herein by reference.

FIELD OF THE INVENTION

The field of present invention relates generally to gas scrubbingequipment and, more particularly, to equipment suitable for scrubbingimpurities from high volume gas streams without creating a significantrise or increase in back pressure.

BACKGROUND OF THE INVENTION

Gas scrubbers are used in many industrial processes and applications toclean, remove or “scrub” certain undesirable gaseous components from gasstreams in general. One area in which a large number of developmentshave been made is in the scrubbing of gases produced during, or relatedto, oil and gas recovery and storage operations. Examples of operationswhere a gas scrubber is typically used include loading andtransportation of sour liquids, venting storage tanks during completionoperations and well testing, purging of vessels and pipelines, bleedingoff wellheads, venting settling tanks for underbalanced drilling,controlling emissions and odors from industrial processing, controllingvacuum truck emissions and odor control during plant turn-around andtank cleaning operations.

During such operations, poisonous hydrogen sulfide (H₂S) presentpresents a health hazard to workmen in the area. To protect the workmenand the public-at-large, the permissible conditions and levels foremissions of hydrogen sulfide are regulated by various regulatoryagencies.

Conventional systems for the absorption or removal of unwantedcontaminants from a gas source or stream often employ a liquid solventor scavenger to “scavenge” out the H₂S. An example of such a treatmentliquid is the hydrogen sulfide scavengers HSW705 and HSW700 manufacturedby Baker Petrolite of Sugar Land, Tex., U.S.A. Information supplied byBaker Petrolite notes that the HSW705 formulation is specificallydesigned to remove hydrogen sulfide from produced gas and that thisliquid product combines with hydrogen sulfide (H₂S) to form stable,water-soluble reaction products that may be easily removed from thesystem. Baker Petrolite recommends that the point of injection of thescavenging chemical be as early as conveniently possible in theproducing system to maximize contact time, i.e. injection downhole orbefore wellhead chokes are generally the best points of application.However, this may be impractical in some of the operations noted above,such as during the loading and transportation of sour liquids, ventingstorage tanks during completion operations and well testing, purging ofvessels and pipelines, venting settling tanks for underbalanceddrilling, controlling emissions and odors from industrial processing,controlling vacuum truck emissions and odor control during plantturn-around and tank cleaning operations.

Likewise, Am-Gas Scrubbing Systems (1989) Ltd. of Didsbury, Alberta,Canada distributes and markets chemical products under the trademarkPARATENE, which are used as hydrogen sulfide scavengers for use inoilfield and industrial applications and, depending on the exactformulation, forms either water-soluble or oil-soluable by-products.Examples include PARATENE M310, PARATENE M311, PARATENE M315, PARATENEM316, PARATENE M320 and PARATENE M330.

The prior art is replete with various examples of devices and methodsfor the “scrubbing” of gas streams using such treatment liquids orliquid scavengers. However, none of the prior art devices provide arelatively portable device which is capable of efficiently removinggases like hydrogen sulfide quickly from large volumes of influent gasand without creating a significant amount of back-pressure. Furthermore,prior art devices have problems with liquid scavenger chemical exitingout of the devices when back-pressures are low, problems with dealingwith the high gas volumes and flow rates when they are hooked up to avacuum truck and problems with providing sufficient contact time toallow the liquid scavenger to treat the gas and remove or “scrub” thehydrogen sulfide. The present invention addresses these problems.

SUMMARY OF THE INVENTION

In one aspect of the invention there is provided a gas scrubbing systemfor removing contaminants from a flow of fluid, comprising: a containerhaving an interior volume, an inlet for receiving the flow of fluid andan outlet for dispensing the stream of fluid, a treatment liquid, acontact cell positioned in the interior volume, between the inlet andoutlet, for providing a high surface area to facilitate chemicalinteractions between the fluid flow and the treatment liquid and meansto apply the treatment liquid onto the contact cell.

In another aspect of the invention there is provided a contact cell foruse in a gas scrubbing system, comprising a layer of poly-propylenebeads.

In a method aspect, a method to purify a stream of gas is provided. Themethod comprises the steps of providing a treatment liquid, treating thestream of gas with a first separator to remove any liquid and solidcontaminants, scrubbing the stream of gas with a liquid scavenger andtreating the scrubbed stream of gas with a second separator to removeany remaining liquid scavenger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of one embodiment of the gas scrubber according tothe present invention;

FIG. 2 is a diagrammatic front sectional view of the gas scrubber of theembodiment of FIG. 1;

FIG. 3 a is a diagrammatic side sectional view of a preferred embodimentof a contact cell;

FIG. 3 b is a diagrammatic side sectional view of a second embodiment ofa contact cell;

FIGS. 4-5 are front perspective views of the gas scrubber of theembodiment of FIG. 1;

FIGS. 6-9 are top perspective view the gas scrubber of the embodiment ofFIG. 1, looking down into the interior volume of the scrubber;

FIG. 10 is a front view of a second embodiment of the gas scrubber;

FIG. 11 is a top view of the gas scrubber of the embodiment of FIG. 10;and

FIGS. 12 a-12 c are cut-out perspective and top views of anotherembodiment of the gas scrubber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description are of preferred embodiments by way of exampleonly and without limitation to the combination of features necessary forcarrying the invention into effect. Reference is to be had to theFigures in which identical reference numbers identify similarcomponents. The drawing figures are not necessarily to scale and certainfeatures are shown in somewhat schematic form in the interest of clarityand conciseness.

Referring to the Figures generally, one embodiment of a gas scrubbingsystem constructed in accordance with the present invention 10 isillustrated in FIGS. 1-9, a second embodiment of a gas scrubbing systemconstructed in accordance with the present invention is illustrated inFIGS. 10-11 and a third embodiment of a gas scrubbing system constructedin accordance with the present invention is illustrated in FIGS. 12 a-12c. The three embodiments are similar to each other, differing only inminor aspects as shown in the figures and as further described below.Operation of the three embodiments is also similar, again with thedifference between them as shown in the figures and as further describedbelow.

Referring to the Figures generally, the scrubber system 10 comprises amain vessel or container 12. The vessel 12 has an interior volume 12 v,an inlet 12 i for receiving a predetermined mass flow rate of gas, thatmay be contaminated by a pollutant such as hydrogen sulfide, and anoutlet 12 o for dispensing the gas once it has been treated with atreatment liquid, scrubber solution or scavenger 22, 24. The flow of thegas is from the inlet 12 i to the outlet 12 o and is shown generally bythe arrows designated as 15. Preferably the treatment liquid 22, 24 isone of the hydrogen sulfide scavengers distributed by Am-Gas ScrubbingSystems (1989) Ltd. of Didsbury, Alberta, Canada under the PARATENEtrademark.

A preferred material for the vessel 12 is steel. In this embodiment, thevessel 12 is conveniently in the form of a hollow box having a closedbottom 12 b and vertical side walls 12 w and measuring approximately 44inches long by 29 inches wide and 67 inches high. Preferably the system10 further comprises an open top 16 and a detachable or removable lid18. Alternatively, the system 10 may take any other suitable form, suchas that of a drum, without departing from the spirit or scope of thisinvention. Preferably the vessel 12 is a pressure vessel capable oftolerating gas pressures of 1.5 pounds per square inch (psi) or higher.

The system 10 further comprises at least one suitable conventional spraynozzle 20 to convert a source of liquid scavenger 22 into a spray ofdroplets 24. The spray nozzle 20 is provided or mounted to the vessel 12so as to inject or introduce the liquid scavenger 24 into the upperportion of the vessel's interior volume 12 v. Preferably a plurality ofnozzles 20 are provided at various positions inside the vessel'sinterior 12 v. The embodiment of FIGS. 1-9 has two nozzles 20 dependingfrom the lid 18 (see FIG. 2) and three nozzles 20 positioned as shown inFIG. 8. The embodiment of FIGS. 10-11 has three nozzles depending fromthe lid. The embodiment of FIGS. 12 a-12 c, like that of the firstembodiment, has as two nozzles 20 depending from the lid (not shown) andthree nozzles 20 positioned as shown in FIG. 12 a.

More preferably, pumping means, in this embodiment comprising a pump 26along with associated hosing and tubing 28, are provided to link thesource of liquid scavenger 22 to the nozzles 20 in a conventionalmanner. Even more preferably, the pump is capable of pumping at least 10gallons per minute so as to ensure that the porous medium 30 remainssubstantially wetted with liquid scavenger 22 during operations.

Yet even more preferably, the lower portion of the vessel's interiorvolume 12 v functions as a retaining reservoir for the source of liquidscavenger 22. Advantageously, the liquid scavenger 24 released from thenozzle 20, or nozzles 20, in the upper portion of the vessel's interiorvolume 12 v descends to the lower portion and once again become part ofthe source 22.

The system 10 further comprises a high surface area, porous substrate ormedium 30 which is placed inside the vessel 12 and in the path of theflow of the gas 15 as it moves from the inlet 12 i to the outlet 12 o.The porous medium 30 minimizes disruption of the normal flow pattern ofthe flow of gas 15 through the system 10 while at the same timeproviding a high surface area to carry treatment liquid 22, 24 thatcoats the medium, thereby allowing the system 10 to treat high volumegas streams without creating a significant rise or increase in backpressure.

In this embodiment, the porous medium 30 is in the form of a 6-inch deepbed of approximately ⅛^(th) inch diameter poly-propylene beads 32,measuring approximately 44 inches by 22 inches for a total volume ofapproximately 5808 cubic inches of ⅛th inch poly-propylene beads. Suchpoly-propylene beads 32 are distributed by Ashland Canada Corp ofRichmond, B.C., Canada. The porous medium 30 is located within theinterior volume 12 v so as to be substantially “wetted” or coated by thedroplets of scavenger 24 exiting the nozzles 20 while at the same timebe in the path of all, or substantially all, of the flow of the gas 15as it moves from the inlet 12 i to the outlet 12 o. Advantageously, thissubstantially “wetted” high surface area medium 30 provide for numerousinteraction sites for treatment liquid 22 to interact with the gas flow15. More advantageously, the continual circulation of treatment liquid22 (by the pump 26) from the source, through the nozzle 20, or nozzles20, across the porous medium 30 and back to the source results in anefficient use of said treatment liquid 22.

The inventor has observed that using a porous medium 30 with a thicknessrange of about 6 inches to 30 inches of beads 32 resulted in goodscrubbing or treating performance by the system 10, allowing the system10 to treat high volumes and flow rate gas streams 15 without creating asignificant rise or increase in back pressure.

Preferably, the porous medium 30 is in the form of a contact cell 30 cand of such dimensions so as to be in the path of most or all of theflow of gas 15. More preferably the dimensions of the contact cell'speriphery are such that a very close tolerance fit is obtained when thecontact cell 30 c is placed inside the vessel, thereby providing littleroom or space for gas to flow around the cell 30 c.

More preferably the contact cell 30 c further comprises two ½ inchthicknesses of ⅛ inch thick reticulated open-cell foam layers 33 placeddirectly below and an top of the porous medium (see FIG. 3 a). Suchreticulated open-cell foam layers 33 is distributed by NorwescoIndustries (1983) Ltd. of Calgary, Alberta, Canada. Even morepreferably, the contact cell 30 c is removable by surrounding orencasing the 6-inch bed of beads 32, and the open-cell foam 33, with a1/16th inch screen material 30 m at the top and bottom and enclosing thesides 30 s with ⅛^(th) inch steel (see FIG. 3 a). Advantageously, thethicknesses of open-cell foam 33 provides additional stability andcushioning to the contact cell 30 c as a whole and keeps the beads 32well packed. More advantageously, the relatively thin layers of foam 33(only ½ inch total thickness at both top and bottom) acts as a filtermaterial, preventing dirt and debris from lodging in the beads 32, whileallowing the flow of gas 15 through without significantly increasing theback pressures.

Even more preferably, sealing means (not shown) are used to seal theperiphery of the contact cell 30 c against the interior walls of thevessel 12, thereby ensuring that all of the flow of gas is directedthrough the contact cell 30 c. The inventor initially utilized aEthylene Propylene Diene Monomer (EPDM) seal for this purpose. Thisworked well initially. However, after some time this seal underwent someshrinkage and needed to be replaced. It is speculated that thisshrinkage was due to heat. Subsequent experimentation with a buna sealshowed that this type of seal did not undergo this kind of shrinkage andtherefore lasts longer. It is to be understood that a seal or sealingmeans is not critical to the invention.

Advantageously, the contact cell 30 c provides for easy containment ofthe beads 32, thereby allowing them to be easily removed, cleaned,replaced and/or serviced when dirty. More advantageously, the contactcell 30 c prevents shifting of the beads 32 during operations onunleveled ground or during transportation of the system 10.

The inventor estimates that providing the above-noted 6-inch deep bed ofapproximately ⅛^(th) inch diameter poly-propylene beads 32, measuringapproximately 44 inches by 22 inches and having a cross sectional areaof 968 square inches and total volume of 5808 cubic inches, results in asurface area of approximately 81,312 square inches plus-or-minus 25%.The inventor observed that using the above-noted contact cell 30 cconfiguration, with the layers of open-cell foam 33, and said cell 30 cbeing substantially wetted with treatment liquid 22, 24 during gasscrubbing operations, resulted in back pressure of only approximately18″ water column with a flow rate of approximately 800 standard cubicfeet per minute across said bed.

Another embodiment of a contact cell 30 c (see FIG. 3 b) comprises two ½inch thicknesses of mist eliminators or demister pads 34 instead ofreticulated open-cell foam 33, but is otherwise similar to theembodiment of FIG. 3 a. Such demister pads 34 are distributed byIndustrial Process Products Ltd. of Calgary, Alberta, Canada.Advantageously, the use of demister pads 34 provides for even less backpressures during operations than a similar thickness of reticulatedopen-cell foam. The inventor observed that using a substantially wetted(with treatment liquid 22) contact cell 30 c configuration of 10½-inchdeep bed of approximately ⅛^(th) inch diameter poly-propylene beads 32,measuring approximately 44 inches by 22 inches and having a crosssectional area of 968 square inches, but with the two layers of ½ inchthick demister pad 34 (instead of the layers of open-cell foam 33),during gas scrubbing operations resulted in very similar back pressures,again of only approximately 18″ water column with a flow rate ofapproximately 800 standard cubic feet per minute across said bed.However, by using a 10½-inch deep bed of beads 32, the total surfacearea provided increased significantly (estimated by the inventor to beapproximately 142,296 square inches, plus-or-minus 25%).

During operations, the inventor observed that, when using this secondembodiment of contact cell 30 c (i.e. having demister pad materialinstead of open-cell foam) in the system 10 of the embodiment shown inFIGS. 12 a-12 c, the system 10, using approximately 410 liters ofPARATENE M320 treatment liquid 24, was able to completely scrub a 1½percent sour (H₂S) flow of gas 15 (i.e. resulting in 0 ppm H₂Sconcentration at the outlet) having a flow rate of 800 cubic feet perminute and only created a back pressure of approximately 18″ watercolumn.

As will be appreciated by those skilled in the art, a number of factorswill determine how long a particular batch of treatment liquid 24 willlast before said batch 24 becomes spent and the system 10, duringoperation, will start showing signs of H₂S breakthrough at the outlet 12o, such as H₂S concentrations in the range of 5-25 ppm at the outlet.One factor is the particular treatment liquid used. Another factor isthe amount of treatment liquid used (for example, one would expect a 200liter batch of treatment liquid to last roughly half as long as a 400liter batch, assuming all other factors are equal). A third factor isthe H₂S concentration in the flow of gas 15. A forth factor is thevolumetric flow rate of gas 15 through the system.

Observations:

When using 410 liters of PARATENE M320 treatment liquid 24 in the system10 of the embodiment shown in FIGS. 12 a-12 c with the second embodimentof the contact cell 30 c (FIG. 3 b) and a gas flow 15 rate of 1400standard cubic feet per minute (SCFM), the inventor has observed thefollowing:

(i) light duty operation, of scrubbing a gas flow with 2,000 ppm H₂Sconcentration at the inlet 12 i, resulted in the system 10 being able tooperate for 50 hours or more before any signs of H₂S breakthrough at theoutlet 12 o; and

(ii) heavy duty operation, of venting two storage tanks at approximately80,000 ppm H₂S concentration at the inlet 12 i, resulted in the system10 initially having a 20 ppm H₂S concentration at the outlet 12 o, withthis having increased to 80 ppm H₂S concentration after one hour ofoperations.

When the treatment liquid 24 starts showing signs of breakthrough, i.e.it becoming less effective at combining with hydrogen sulfide (H₂S) toform stable end products and resulting in an unacceptable concentrationof H₂S at the outlet (such as an H₂S concentration greater than 10 ppm),the liquid scavenger 24 can be drained from the system 10 and replacedwith a fresh batch of such treatment liquid 24.

Using a contact cell 30 c composed only of demister pad material 34 (seeFIGS. 6-7) proved to be cost prohibitive in that a given thickness ofdemister pad is much more expensive that a given thickness ofpoly-propylene beads 32 and the surface/contact area provided bydemister pads is significantly inferior to the amount of surface areaprovided by a similar thickness of poly-propylene beads 32.

Similarly, the inventor has observed that using glass particles, insteadof poly-propylene beads also had disadvantages. Although glass particlesprovide a similar amount of surface area per unit volume, as compared tothe poly-propylene bead, one of the disadvantage of such glass particlesis that over time they could break into even smaller pieces which mayescape from the contact cell and can get caught in the pump 26,potentially damaging the pump's internal mechanisms.

Preferably, the scrubber system 10 further comprises an inlet separator40 and catch reservoir 41 associated with the vessel's inlet 12 i and anoutlet separator 42 associated with the vessel's outlet 12 o. Morepreferably, the inlet and outlet separators 40, 42 are cycloneseparators (see FIG. 2). Cyclone separators as such are well-known inthe art and rely on generated centrifugal and shear forces to achieveseparation into two streams of different densities.

Briefly and as shown in FIG. 2, the cyclone separators 40, 42 comprisesa chamber 40 c, 42 c having a vertical axis with an upper cylindricalportion 40 u, 42 u and a lower, inverted frustro-conical portion 40 f,42 f. The mixture is introduced through a tangential inlet 12 i, 42 i tothe cyclone separator, which causes heavier particles to be flung, undercentrifugal force, against the outer wall of the chamber and flowdownwardly along, as underflow, and around the wall to a lower axialoutlet 401, 421, while the lighter, remaining, proportion of the mixtureis drawn off by an axial pipe, known as a vortex finder 40 v, 42 v, froma point within the body of the cyclone separator 40, 42 as overflow andconveyed overhead through upper axial outlet 40 u, 42 u. One form ofcyclone separator is disclosed in U.S. Pat. No. 4,737,271, but otherforms of cyclone separators are known in the art and may also be used.The cyclone separators are preferably used, for the reason that acyclone separator is a simple, reliable and relatively inexpensive pieceof equipment that is highly effective in separating lower and higherdensity materials.

Other forms of inlet and outlet separators 40, 42 may be utilized. Forexample, FIGS. 12 a-12 c illustrate another embodiment of the system 10wherein the separators 40, 42 comprise a generally cylindrical chamber40 c, 42 c having a vertical axis, an upper axial outlet 40 u, 42 u andan internal cylindrical member 40 m, 42 m positioned around the upperaxial outlet 40 u, 42 and depending partway downward into the separator40, 42. The cylindrical member 40 m has a bottom axial opening 40 b, 42b. The mixture is introduced into the separator 40, 42 through one ormore a tangential inlets 12 i, 42 i, which, under gravitational andcentrifugal forces, causes heavier particles to be flung against theouter wall of the separator and flow downwardly to the bottom of theseparator 40, 42, while the lighter, remaining, gaseous mixture isforced around the cylindrical member 40 m in a generally downward rotarymotion until conveyed into the cylindrical member 40 m (through itsbottom axial opening 40 b, 42 b) and finally out through upper axialoutlet 40 u, 42 u.

Advantageously, the inlet separator 40 facilitates the removal ofcontaminants 41 c such as oil, water and dirt from the inlet flow offluid prior to entering the interior volume 12 v (through passage 70)and directing said contaminants 41 c into the catch reservoir 41,thereby preventing such contaminants 41 c from plugging or contaminatingthe contact cell 30 c. More advantageously, the outlet separator 42facilitates separation of any liquid scavenger 24 from the gaseous flow15 (coming via inlets 42 i), that did not fall back into the source 22,prior to the gaseous flow exiting of the vessel 12 through the outlet 12o. Even more advantageously, the axial outlet 421 directs any separatedout scavenger 24 back to the main source 22, preferably via openings 65.Alternatively, other forms of separators may be utilized.

As noted above, the contact cell 30 c provides a high surface area forthe liquid scavenger 22, 24 to cling to, and/or coat, while stillallowing for the gas flow 15 to move therethrough without producting agreat deal of back pressure. The contact cell 30 c, along with theliquid scavenger 22, 24, thereby creates a gas filtering means thatresults in an efficient absorption of the contaminants (such as hydrogensulfide) by the scavenger 22, 24 without creating a large amount of backpressure compared to that in conventional absorption towers or columns(where gas is typically allowed to bubble through a volume of liquidscavenger).

Preferably, the gas scrubbing system 10 further comprises one or morevalved drains 50, 52 to allow an operator to drain away any contaminants41 c from the inlet separator 40 and/or liquid scavenger 24 from thesystem 10. In this embodiment, drain 50 is associated with the inletseparator 40 to facilitate draining of any contaminants 41 c and drain52 is associated with the scavenger 24 reservoir to facilitate drainingof said scavenger 24. Even more preferably, the scrubber system 10further comprises a burst plate 60 associated with the inlet 12 i, so asto protect the vessel 12 and/or any vacuum pump (not shown) that may behooked up to the system 10 from damage due to excess pressures.Preferably the burst plate 60 is set to burst at 5 psi.

Those of ordinary skill in the art will appreciate that variousmodifications to the invention as described herein will be possiblewithout falling outside the scope of the invention.

1. A gas scrubbing system for removing contaminants from a flow offluid, comprising: a container having an interior volume, an inlet forreceiving the flow of fluid and an outlet for dispensing the flow offluid; a treatment liquid; a porous medium positioned in the interiorvolume, between the inlet and outlet, for providing a high surface areato facilitate chemical interactions between the fluid flow and thetreatment liquid; and means to apply the treatment liquid onto theporous medium.
 2. The gas scrubbing system of claim 1 wherein the porousmedium is a contact cell and further comprises a layer of poly-propylenebeads.
 3. The gas scrubbing system of claim 2 wherein the diameter ofthe poly-propylene beads is in the range of 1/16^(th) to ¼^(th) of aninch.
 4. The gas scrubbing system of claim 2 wherein the contact cellfurther comprises two layers of reticulated foam positioned above andbelow the layer of poly-propylene beads.
 5. The gas scrubbing system ofclaim 2 wherein the contact cell further comprises two layers ofdemister pad material positioned above and below the layer ofpoly-propylene beads.
 6. The gas scrubbing system of claim 1 furthercomprising an inlet separator associated with the inlet, wherein theinlet separator facilitates the removal of contaminants from the flow offluid prior to said flow entering the interior volume.
 7. The gasscrubbing system of claim 1 further comprising an outlet separatorassociated with the outlet, wherein the outlet separator facilitatesseparation of any liquid scavenger from the fluid flow, prior to saidfluid flow exiting through the outlet.
 8. A contact cell for use in agas scrubbing system, comprising: a layer of poly-propylene beads. 9.The contact cell of claim 8 wherein the diameter of the poly-propylenebeads is in the range of 1 1/16^(th) to ¼^(th) of an inch.
 10. Thecontact cell of claim 9 further comprising two layers of reticulatedfoam positioned above and below the layer of poly-propylene beads. 11.The contact cell of claim 9 further comprising two layers of demisterpad material positioned above and below the layer of poly-propylenebeads.
 12. A method to purify a stream of gas comprising: providing atreatment liquid; treating the stream of gas with a first separator toremove any liquid and solid contaminants; scrubbing the stream of gaswith said treatment liquid; and treating the scrubbed stream of gas witha second separator to remove any remaining treatment liquid.
 13. Themethod of claim 12 wherein the scrubbing step further comprises:providing a porous medium; substantially wetting the porous medium withthe treatment liquid; and passing the stream of gas through said wettedporous medium.
 14. The method of claim 13 wherein the porous mediumfurther comprises a layer of poly-propylene beads.
 15. The method ofclaim 14 wherein the diameter of the poly-propylene beads is in therange of 1/16th to ¼th of an inch.